Inflatable packing for stuffing boxes

ABSTRACT

An inflatable packing gland for stuffing boxes utilized around the reciprocal polished rod of a producing oil well wherein the pressure of the packing member against the outer periphery of the polished rod may be automatically maintained at the most desirable level regardless of wear on the inner periphery of the stuffing gland.

United States Patent Inventors Alvin G. Burns 1020 E. 34th St.;

Sheldon M. Miller, 4636 S. Wheeling, Tulsa, Okla. 74105 Oct. 3, 1969 May 25, 1971 Continuation-impart of application Ser. No. 633,664, Apr. 12, 1967, now Patent No. 3,471,156.

Appl. No. Filed Patented INFLATABLE PACKING FOR'STUFFING BOXES 4 Claims, 4 Drawing Figs.

u.s.c| 277/3, 277/28, 166/84 1nt.Cl Fl6j 15/40, F16j 15/00, F16j 9/00 FieldoiSearch 277/3,34,

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[56] References Cited UNITED STATES PATENTS 1,772,210 8/1930 Dale 277/34X 1,861,726 6/1932 Trout 277/34X 2,193,587 3/1940 Fortune et al. 277/34 2,307,575 1/1943 Davis..... 277/34X 2,567,479 9/1951 Hebard..... 277/3 2,841,422 7/1958 Badger 277/34 Primary Examiner-Samuel B. Rothberg AttorneyWilliarn S. Dorman ABSTRACT: An inflatable packing gland for stuffing boxes utilized around the reciprocal polished rod of a producing oil well wherein the pressure of the packing member against the outer periphery of the polished rod may be automatically maintained at the most desirable level regardless of wear on the inner periphery of the stuffing gland.

PATENTEU W25 1971 SHEU 1 OF 2 z Ka vv ALVIN G BURNS HELDON M. MILLER INVENTORS ATTORNEY PATENTEUHAYZSIBYI 3580.586

SHEET 2 OF 2 ALVIN G. BURNS SHELDON M.MILLER INVENTORS ATTORNEY INFLATABLE PACKING FOR STUFFING BOXES This is a continuation-in-part application of our copending application Ser. No. 633,667, filed Apr. 12, 1967, now U.S. Pat. No. 3,471,156 and entitled Inflatable Packing for Stuffing Boxes. This invention relates to packing glands and more particularly, but not by way of limitation, to an inflatable packing for stuffing boxes, or the like, such as utilized around the polished rod of a producing oil well.

Most producing oil wells today do not have sufficient well pressures to provide for a natural flow of the well fluid and as a result, some means must be utilized for elevating the well fluid to the earths surface. A majority of the producing oil wells utilize pumping means actuated by a reciprocating rod. The pumping unit itself is normally installed near the bottom of the well bore and is actuated by a string of rods extending downwardly through the well bore from the surface of the ground. The uppermost rod which projects from the wellhead is commonly called the polished rod. A packing gland or stuffing box is usually secured to the wellhead around the polished rod to prevent a leakage of the pumped oil around the rod. Packing rings or packing glands of various types are normally disposed within the stuffing box and bear against the outer periphery of the polished rod to provide a sealing engagement therearound.

The reciprocation of the rod with respect to the packing rings wears the inner periphery of the packing rings substantially rapidly thus requiring rather frequent manual attendance at the stuffing boxes to assure an efficient sealing action around the polished rod. Follower members, and the like, are usually provided with these stuffing boxes which may be manually tightened for increasing the sealing engagement of the packing members when they become worn. This is a mechanical tightening operation for increasing the pressure of the packings against the polished rod and it is difficult to ascertain exactly how much pressure is exerted against the polished rod upon tightening of the follower members. If the packing members bear against the polished rod with insufficient pressure, the sealing may be inefficient and the well fluid may leak around the rod. Conversely, if the packing members are too tightly wedged in engagement with the polished rod, the reciprocation of the polished rod will be somewhat hindered and wear of the packing members will be greatly increased thus requiring more frequent replacement of the packing members.

Producing oil wells are frequently situated in remote locations making manual attendance thereto somewhat disadvantageous. As a result, almost all of the operation equipment required for the pumping of the well fluid are automatically controlled, with the exception of the stuffing boxes. The rapid wear of the packing rings in the stufiing boxes requires frequent attention for correction of the sealing pressure or for replacement of the packing rings and it is considered that a reduction of any necessary manual attention to the stuffing box would be of great advantage.

The present invention contemplates a novel inflatable packing member for a stuffing box wherein the pressure of the packing member against the outer periphery of the polished rod may be maintained at the most desirable predetermined or preselected level regardless of wear on the inner periphery of the packing member due to the reciprocation of the polished rod. The novel inflatable packing is disposed within the stuffing box with the inner periphery thereof in sealing engagement with the polished rod. An annular chamber is provided around the outer periphery of the packing member for receiving a fluid therein whereby equal pressure will be exerted radially inwardly to assure a constant and efficient sealing between the stuffing box and polished rod. The well pressure itself is utilized for amplification of the sealing pressure, thus assuring an efficient sealing even under extremely high well pressure conditions. The pressure of the packing member against the polished rod may be automatically maintained at a sufficient level for efficiently packing off around the rod without hampering the reciprocation of the rod within the stufflng box, regardless of the well pressures which maybe acting on the stuffing box.

When wear occurs on the inner periphery of the inflatable packing member, the inner diameter thereof will be slightly enlarged but the pressure of the fluid within the annular chamber, acting radially on the outer periphery of the packing member, will constantly urge the inner periphery of the inflatable packing into an efficient sealing engagement with the polished rod. In addition, the inner periphery of the inflatable packing member is particularly constructed for facilitating contraction thereof around the rod. The need for follower members, and the like, is eliminated since the packing member is constantly maintained in sealing engagement with the polished rod with the adjustment of the sealing pressure being automatically achieved as wear occurs and automatically adjusted in accordance with the requirements for sealing off the well pressure. It will be apparent that the efficient life of the inflatable packing member is greatly prolonged and manual attention for adjusting of the sealing pressure is substantially eliminated, the need for manual attendance at the well site is greatly reduced. The novel packing member may be utilized with substantially any existing stufflng box, such as generally similar to that disclosed in the Sheridan P. Tschappat U.S. Pat. No. 2,857,183, issued Oct. 21, 1958 and entitled Reservoir Gland Stuffing Box," but is not limited thereto. It is to be understood that whereas the novel packing member is depicted herein as utilized with an oil well stuffing box, it is anticipated that the packing member may be utilized in any suitable environment requiring this type of sealing.

It is an important object of this invention to provide an improved oil well stuffing box having an inflatable packing member therein for sealing around the polished rod of an oil well pumping device wherein manual attendance of the stuffing box is reduced to a minimum.

It is another object of this invention to provide a novel inflatable packing member for an oil well stuffing box wherein the sealing engagement between the packing member and oil well polished rod may be automatically maintained at an optimum pressure regardless of pressures in the well bore acting on the stuffing box.

Another object of this invention is to provide a novel inflatable packing member for an oil well stuffing box wherein the pressure of the packing member against the polished rod may be regulated to provide a known preselected pressure for the packing member.

Still another object of this invention is to provide a novel inflatable packing member for an oil well stuffing box wherein the well pressure is utilized for amplifying the sealing pressure of the packing member against the polished rod.

A further object of this invention is to provide a novel inflatable packing member for an oil well stuffing box wherein an efiicient sealing is provided for the polished rod without interference with the reciprocation of the rod.

A still further object of this invention is to provide a novel packing member for an oil well stuffing box which is simple and efficient in operation and economical and durable in construction.

Other and further objects and advantageous features of the present invention will hereinafter more fully appear in connection with a detailed description of the drawings in which:

FIG. 1 is a sectional elevational view of a stuffing box and packing member embodying the invention.

FIG. 2 is a sectional view taken on line 2-2 of HO. 1.

FIG. 3 is a broken sectional view depicting a spring-loaded yoke member utilized in the invention.

FIG. 4 is a elevational view of a stuffing box embodying the invention and depicted in connection with the pumping tee of an oil well.

Referring to the drawings in detail, reference character 10 generally indicates an oil well stuffing box having the usual polished rod 12 extending longitudinally therethrough and reciprocal therein, as is well known. The stuffing box 10 comprises a substantially cylindrical central body member or housing 14 loosely disposed around a portion of the polished rod 12 for providing an annular chamber 16 therearound. The sleeve or body 14 is provided with a plurality of outwardly extending flanges or ears 1% (FIGS. 2 and 4) in the proximity of the lower end thereof as viewed in FIGS. l and 4 and which is disposed on or supported by complementary or corresponding outwardly extending flanges provided in the proximity of the upper end of a support sleeve or housing 22. The flanges 18 and 20 may be removably secured together in any wellknown manner, such as by a plurality of bolts 24 and complementary nuts 26, or the like.

The lower end of the housing 22 terminates in a tubular or cylindrical portion 28 having an externally threaded portion 30 for connection with the wellhead pumping tee 32, or the like.

A packing member generally indicated at 34 is disposed within the body 14 and is supported therein by the upper end 36 of the support housing 22. The packing member 34 may be constructed from any suitable material, such as rubber, neoprene, moly-disulfide, plastic, or the like, which may be expanded and contracted upon the application of pressure, as will be hereinafter set forth in detail. The packing member 34 comprises a sleeve 38 concentrically disposed around the outer periphery of the rod 12 and having an outwardly extending circumferential flange 410 provided at the lower end thereof as viewed in FIG. l. The flange 40 is disposed on the surface 36 and is provided with a circumferentially extending bulbous portion 42 around the outer periphery thereof within an annular groove Ml provided in the lower end of the body 114. The flange M is secured between the abutting ends of the housings 114 and 22 and performs a dual function; namely, to anchor the packing member 34 in the chamber 16 and to provide a seal between the housings 1 3 and 22. The bulbous portion 44 functions in much the same manner as an O-ring, or the like, for facilitating the sealing of the junction between the housing 14 and 22.

As hereinbefore set forth, the sleeve 38 is disposed around the outer periphery of the rod 12 and extends upwardly in the chamber l6 from the surface 36 to the proximity of the upper end of the body M. The upper end of the sleeve 38 is substantially tubular, but may extend slightly upwardly and outwardly, as shown in FIG. ii, if desired, and for a purpose as will be hereinafter set forth. The uppermost end of the sleeve 38 is provided with an outwardly extending circumferential flange which may be bulbous if desired and is disposed on an annular shoulder 43 provided on the inner periphery of the sleeve or body 14 for supporting the sleeve 38 in the chamber 116 to provide a seal between the housing 14 and a follower member 50.

It will be apparent that the inner periphery of the sleeve 38 may be substantially smooth, if desired, for engaging the outer periphery of the polished rod 12. However, it is preferable to provide a plurality of longitudinally spaced annular recesses 52 extending radially from the inner periphery of the sleeve 38. The recesses 52 may be provided with slightly angularly disposed or tapered upper and lower sidewalls, as shown herein, or straight upper and lower sidewalls. A plurality of longitudinally spaced ribs 54 are formed between each adjacent pair of recesses 52 and provide a sealing effect similar to that of a plurality of individual sealing rings around the outer periphery of the rod 12. The ribs 54 depicted herein are integral with the sleeve 38, but it is to be noted that separate or individual packing rings may be substituted in lieu of ribs 54. These separate packing rings (not shown) may be of the annular sealing ring type or the chevron type, both of which are well known. Of course, when utilizing separate sealing members in lieu of the integral ribs 54, only the individual sealing elements need be replaced in the event of undue wear during operation of the stuffing box l0.

An inwardly directed annular shoulder 56 is provided on the inner periphery of the housing l4 spaced below the shoulder 418. The shoulder 56 defines the upper end of the chamber 16 and provides a central bore 56 for receiving the upper end of the sleeve 33 therethrough. A pair of oppositely disposed outwardly extending'tlanges 60 (only one of which is shown in FIG. 4) are provided atthe upper; end of the housing M for receiving and supporting complementary outwardly extending flanges 62 provided on the outer periphery of the follower 56. The flanges 60 and 62 may be removably secured together in any well-known manner, such as by a plurality of bolts 64 and cooperating nuts 66, as is well known, In addition, an upstanding sleeve 68 is offset from the bore 58 and is in open communication with the chamber 116 through an angled passageway 70 provided in the housing 141. The sleeve 66 is provided with a central bore 72 having an outwardly extending circumferential shoulder 74 providing an enlarged bore portion 76 conterminous with the bore 72. The bore 76 is threaded for receiving a threaded plug member generally indicated at 73.

The plug 78 may be of a one-piece or integral construction but as shown herein is a two-piece structure comprising an upper threaded sleeve 80 having a lower substantially smoothwalled plug member 82 secured to the lower end thereof by a suitable capscrew 84 The outer diameter of the plug 32 is slightly less than the outer diameter of the threaded sleeve 86 to provide an annular shoulder 86 between the sleeve 36 and plug 82 for a purpose as will be hereinafter set forth. In addition, an outwardly extending circumferential flange 86 is provided in the proximity of the upper end of the sleeve 30 for engaging the upper end of the sleeve 68 for limiting the downward movement of the sleeve 80. A central bore 88 is provided in the sleeve 80 for receiving the capscrew 34, therethrough, and the bore 88 is enlarged at 90 to provide clearance for the head of the capscrew 9t) and to provide an inwardly directed shoulder 92 for limiting the downward movement of the capscrew '90. It is preferable to provide a plurality of longitudinally spaced sealing rings 94 on the outer periphery of the plug member 82 for precluding leakage of fluid between the plug and the sleeve 68. In addition, a port 96 may be provided in the wall of the sleeve 68 in the proximity of the shoulder 74, if desired, for a purpose as will be hereinafter set forth.

The follower member 50 may be of any conventional type and as disclosed herein comprises a centrally disposed downwardly extending substantially tubular member 96 adapted to be inserted within the upper end of the sleeve 36. The member 36 and flanges 6t) and 62 cooperate with the body M for clamping the sleeve 38 securely at the upper end of the body l4, and for effecting an efficient Sealing between the body 14 and the follower 50.

An inwardly directed annular shoulder W6 is provided on the inner periphery of the follower 50 for supporting a suitable bearing sleeve 1162 around the outer periphery of the rod R2. The sleeve 3102 may be constructed from any suitable material, such an an oil-filled bronze, and facilitates the reciprocation of the rod 12 within the stuffing box 112. An annular cover member 106 is removably secured to the upper end of the follower 56 and around the rod H2 in any suitable manner, such as by a plurality of screws 106, and a suitable sealing member 108 may be interposed between the cover 164 and bearing sleeve 162 for precluding leakage of fluid therebetween and around the rod 12. The sealing member as shown herein is of the chevron type, but it is to be understood that any suitable sealing member may be utilized. In addition, a filler port Illltll is provided in the sidewall of the follower 56) for receiving a plug member M2 therein. A suitable lubricating fluid may be injected into the interior of the follower member 56 through the port l M, as is well known.

The interior of the support housing 22 is open to the interior of the well bore (not shown) for receiving fluid pressure therefrom. An outwardly extending boss TM is provided on the outer periphery of the support housing 22 and is provided with an internal passageway M6 for providing a fluid passageway for the well fluid as will be hereinafter set forth.

A cylindrical housing or sleeve 11193 is provided on the housing M offset from the chamber 116 and preferably integral with the housing M, but not limited thereto. An internal web member i126 extends across the sleeve Mt; spaced upwardly from the housing 22 and forms a passageway R22 to provide a communication between-the chamber l6 and a chamber H2 3 formed below the web 120 and in alignment with the passageway 116. A suitable diaphragm member 126 is secured between the sleeve 118 and boss 114 between the chamber 124 and passageway 116 as clearly shown in FIG. 1. The diaphragm 126 is provided with an upwardly extending centrally disposed sleeve 128 having an outwardly extending circumferential flange 130 at the upper end thereof. A plug member 132 is disposed within the sleeve 128 and rests on the upper surface of the diaphragm 126. A plate 134 is disposed adjacent the lower or opposite surface of the diaphragm 126 and is secured thereto by a suitable bolt 136 which extends through the plate 134 and diaphragm 126 and into the plug 132. Thus the plate 134 and plug 132 move simultaneously with the diaphragm 26.

The sleeve 128 extends through a bore 138 provided in the web 120, as particularly shown in FIG. 1. The bore 138 is enlarged at 140 to provide an inwardly directed annular shoulder 142. The upper flange 130 of the sleeve 128 rests on the shoulder 142 and is securely retained in position thereon by a retainer cap 144. The flange 130 may be provided with upwardly and downwardly extending circumferential ribs (not shown) around the outer periphery thereof for seating within complementary annular grooves (not shown) in the flange 142 and cap 144, if desired, in order to assure an efficient securing of the flange 130 on the shoulder 142.

A stem member 146 is provided on the plug 132 and extends upwardly therefrom, as viewed in FIG. 1, through a bore 148 provided in the cap 144. A flange bushing or bearing sleeve 150 is preferably interposed between the stem 146 and bore 148 for facilitating reciprocation of the stem 146. The stem 146 extends upwardly through a yoke member 152 and is secured thereto by a suitable bolt 154. The yoke member 152 has one end pivotally secured at 156 to the cap member 144, and the opposite end thereof rests on a crossbar 158. The crossbar 158 is secured between a pair of spaced upstanding pins 160 and 162.

The pins 160 and 162 are reciprocally disposed within spaced bores 164 (only one of which is shown in FIG. 3) provided in the housing 14. The bore 164 is threaded for receiving a threaded plug 166. An outwardly extending shoulder 168 is provided on the outer periphery of each pin 160 and 162 and a spring 170 is disposed around the lower portion of the pins 161) and 162 and interposed between the shoulder 168 and respective plug member 166 for constantly urging the pins 160 and 162 in an upward direction.

Of course, the upper end of the housing 118 may be closed by a suitable cover member 172 which is removably secured thereto in any suitable manner.

OPERATION The pressure present in the chamber 16 acts radially inwardly on the outer periphery of the packing member 34 and constantly urges the inner periphery of the packing member 34 into a tight sealing engagement with the outer periphery of the reciprocating rod 12, regardless of wear on the inner periphery of the packing member. In order to establish the desired pressure in the chamber 16, the plug 78 may be removed from the sleeve 68 and a suitable hydraulic fluid may be admitted into the chamber 16 through the passageway 70. The fluid will flll the chamber 124, passageway 122, chamber 16, and the bore 72 until the fluid begins to flow out through the relief port 96. The plug 7 8 may then be threadedly secured to the bore 76 whereby the end plug portion 82 thereof will bear against the upper surface of the fluid. As the sleeve 80 is rotated, the plug 82 will slide downwardly in he bore 72 without rotation, which facilitates the insertion of the plug 78. The downward movement of the plug 76 increases the pressure of the fluid acting on the outer periphery of the packing member 34 since the fluid is uncompressible. The amount of pressure thus generated against the packing 34 may be determined by the position of the plug 78 within the sleeve 68, and of course suitable indica (not shown) may be provided on the sleeve 68 and plug 78 for indicating the established pressure within the chamber 16. Of course, the pressure in the chamber 16 is established at the optimum pressure for the operating conditions of the stuffing box 10.

In the event the well pressure drops sufficiently that the pressure differential across the diaphragm 126 provides for a downward movement of the diaphragm, the volume within the chamber 124 will increase, and the pressure acting on the packing 34 will be correspondingly reduced, thus assuring that the pressure of the packing member against the rod 12, while constantly maintained sufficiently great for an efficient sealing, will not be excessive for the sealing requirements.

When the diaphragm 126 moves downwardly, the plug member 132 is pulled downwardly simultaneously therewith and moves the yoke member 152 downwardly against the action of the springs 170. This assured a rigidity for the diaphragm 126 to preclude ineffective flopping or downward movement thereof during times of decreased pressure within the well bore.

In the event the well pressure increases sufficiently for requiring an increased sealing pressure for the packing member 34, the diaphragm 126 will be flexed upwardly whereby the volume'of the chamber 124 is decreased. The pressure of the fluid acting on the outer periphery of the packing member will be correspondingly increased for assuring an efficient and adequate sealing of the polished rod during the time periods of increased well pressure. When the diaphragm 126 moves upwardly, the plug 132 moves upwardly whereby the stem 146 moves the yoke upwardly, thus maintaining stability for the diaphragm 126 during operation of the stuffing box 10.

Of course, the downward movement of the yoke member 152 is limited by the spring members 170, and thus the downward movement of the diaphragm 126 is limited whereby a least a minimum pressure will be maintained against the packing member 34 for maintaining a seal around the polished rod 12 even during any extremely low pressure conditions within the well bore. Thus, should any vacuum conditions or low-pressure conditions exist within the well bore, there will be no complete withdrawal of the packing member 34 from engagement with the outer periphery of the rod 12.

The pressure within the chamber 16 may be also be adjusted or regulated by rotation of the capscrew 84. It is to be noted that the head of the capscrew 84 does not engage the shoulder 92 when the sleeve is fully threaded within the bore 76. Thus, rotation of the capscrew in one direction will cause the independent plug member 82 to move downwardly for increasing the pressure of the fluid within the chamber 16. Conversely, rotation of the capscrew 84 in an opposite direction will raise the plug 82 until it is again brought into engagement with the sleeve 80, thus reducing the pressure of the fluid in the chamber 16.

With regard to the annular ribs 54 and spaces 52 therebetween, it is to be noted that under the normal operating pressures encountered in a producing well, the spaces will never be filled with rubber, but will always remain open, thus reducing the amount of pressure necessary for efficiently sealing the sleeve 38 against the rod 12.

From the foregoing it will be apparent that the present invention provides a novel inflatable packing member for a stuffing box, or the like, and is particularly designed and constructed for maintaining the most desirable sealing engagement around an oil well polished rod at all times during utilization of the stuffing box. The novel inflatable packing eliminates the need for follower members, and the like, which provide for a mechanical tightening of the packing members. In addition, the pressure acting on the inflatable packing member is automatically adjusted to the most desirable condition corresponding to the pressure conditions of the well, thus reducing manual attendance required for maintaining an efficient operation of the stuffing box and assured the most efficient sealing pressure at all times for greatly prolonging the useful life thereof. The novel packing member and stuffing box are simple and efficient in operation and economical and durable in construction.

Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications, apart from the those shown or suggested herein, may be made within the scope of this invention.

We claim:

1. A stuffing box for an oil well reciprocal polished rod comprising a substantially tubular shaped body member loosely disposed around the polished rod, a pressure-sensitive yieldable packing member provided in the body and surrounding the rod, said packing member being provided with a central bore having the inner periphery thereof in constant sealing engagement with the outer periphery of the rod, a pressure chamber provided in the body surrounding the packing member for receiving a pressure fluid therein, filler port means provided on the body for-admitting said pressure fluid to said pressure chamber, adjustable plug means removably secured to said filler port means for selectively adjusting the pressure of the fluid within the pressure chamber, diaphragm means secured to the housing and having one side open to the pressure chamber and the opposite side open to variable pressure in the oil well, said diaphragm being responsive to pressure differentials acting thereon for automatically maintaining the pressure in the pressure chamber at an optimum for maintaining the most efficient sealing engagement of the sleeve against the rod in accordance with the pressure existing in the well, and means provided in the housing for maintaining stability of the diaphragm during operation of the stuffing box.

2. A stuffing box for an oil well reciprocal polished rod as set forth in claim ll wherein the adjustable plug means comprises sleeve means threadedly secured to the tiller port means, surface means carried by the sleeve means for applying variable pressure to the fluid in the pressure chamber upon rotation of the sleeve means within the filler port, and seal means interposed between the plug means and filler port for precluding leakage of fluid therebetween.

3. A stuffing box for an oil well reciprocal polished rod as set forth in claim 1 wherein the adjustable plug means comprises sleeve means threadedly secured to the filler port means, a plug member adjustably secured to the sleeve means, means connecting said plug means with said sleeve means whereby said plug means is movable simultaneously with and independently from the sleeve means for selectively applying variable pressure to the fluid in the pressure chamber, and seal means interposed between adjustable plug member and the filler port for precluding leakage of fluid therebetween.

4. A stuffing box for an oil well reciprocal polished rod as set forth in claim 1 wherein the diaphragm-stabilizing means includes spring-urged yoke means secured between the diaphragm and the housing and movable simultaneously with the diaphragm to provide said stabilization, and means limiting the movement of the yoke means in one direction for limiting the movement of the diaphragm in one direction to establish a minimum limitation for pressure within the pressure chamber. 

1. A stuffing box for an oil well reciprocal polished rod comprising a substantially tubular shaped body member loosely disposed around the polished rod, a pressure-sensitive yieldable packing member provided in the body and surrounding the rod, said packing member being provided with a central bore having the inner periphery thereof in constant sealing engagement with the outer periphery of the rod, a pressure chamber provided in the body surrounding the packing member for receiving a pressure fluid therein, filler port means provided on the body for admitting said pressure fluid to said pressure chamber, adjustable plug means removably secured to said filler port means for selectively adjusting the pressure of the fluid within the pressure chamber, diaphragm means secured to the housing and having one side open to the pressure chamber and the opposite side open to variable pressure in the oil well, said diaphragm being responsive to pressure differentials acting thereon for automatically maintaining the pressure in the pressure chamber at an optimum for maintaining the most efficient sealing engagement of the sleeve against the rod in accordance with the pressure existing in the well, and means provided in the housing for maintaining stability of the diaphragm during operation of the Stuffing box.
 2. A stuffing box for an oil well reciprocal polished rod as set forth in claim 1 wherein the adjustable plug means comprises sleeve means threadedly secured to the filler port means, surface means carried by the sleeve means for applying variable pressure to the fluid in the pressure chamber upon rotation of the sleeve means within the filler port, and seal means interposed between the plug means and filler port for precluding leakage of fluid therebetween.
 3. A stuffing box for an oil well reciprocal polished rod as set forth in claim 1 wherein the adjustable plug means comprises sleeve means threadedly secured to the filler port means, a plug member adjustably secured to the sleeve means, means connecting said plug means with said sleeve means whereby said plug means is movable simultaneously with and independently from the sleeve means for selectively applying variable pressure to the fluid in the pressure chamber, and seal means interposed between adjustable plug member and the filler port for precluding leakage of fluid therebetween.
 4. A stuffing box for an oil well reciprocal polished rod as set forth in claim 1 wherein the diaphragm-stabilizing means includes spring-urged yoke means secured between the diaphragm and the housing and movable simultaneously with the diaphragm to provide said stabilization, and means limiting the movement of the yoke means in one direction for limiting the movement of the diaphragm in one direction to establish a minimum limitation for pressure within the pressure chamber. 